01657903

Component

Shrinkage cracking of chemical treated subgrade may cause severe damages to the pavement structure. Drying shrinkage and hydration shrinkage are two major causes for the shrinkage cracking of soils. To study the potential application of Microbial Induced Calcite Precipitation (MICP) in crack remediation, the drying shrinkage of bentonite mixed with bacteria and cementation medium are monitored in the petri dish under controlled temperature and relative humidity conditions. Three control groups are also monitored, in which bentonites are mixed with live bacteria + cementation medium without CaCl2, dead bacteria + cementation medium, and dead bacteria + cementation medium without CaCl2, in order to study the influence of MICP process and microbial activity on soil desiccation cracking. Scanning Electron Microscope images show bacteria survive only on the surface of bentonite after dried. However the MICP occurred at the early stage after mixing bentonite with cementation medium changes soil’s property and leads to a more intact sample while drying. Bentonite mixed with live bacteria tends to form larger cracking polygons. It shows the MICP process as well as the microbial activity have a positive influence on the cracking potential remediation. Further study is required to better explain this phenomenon and to discuss the potential field applications.

This paper was sponsored by TRB committee AFP40 Standing Committee on Geo-Environmental Processes.

18-04898

English

11p

2018

Transportation Research Board 97th Annual Meeting

Digital/other

Figures; References; Tables

Bacteria; Bentonite; Calcites; Chemical processes; Precipitation (Chemistry); Shrinkage; Soil remediation

Construction; Geotechnology; Materials; Transportation (General)

Transportation Research Board Annual Meeting 2018 Paper #18-04898

TRIS, TRB, ATRI

Jan 8 2018 11:13AM